| Year | Count |
|---|---|
| 1978 | 5 |
| 1980 | 15 |
| 1981 | 24 |
| 1982 | 26 |
| 1983 | 29 |
| 1984 | 60 |
| 1985 | 205 |
| 1986 | 315 |
| 1987 | 306 |
| 1988 | 432 |
| 1989 | 719 |
| 1990 | 496 |
| 1991 | 539 |
| 1992 | 403 |
| 1993 | 364 |
| 1994 | 213 |
| 1995 | 170 |
| 1996 | 133 |
| 1997 | 98 |
| 1998 | 85 |
| 1999 | 119 |
| 2000 | 89 |
| 2001 | 67 |
| 2002 | 39 |
| 2003 | 44 |
| 2004 | 61 |
| 2005 | 63 |
| 2006 | 57 |
| 2007 | 45 |
| 2008 | 107 |
| 2009 | 39 |
| 2010 | 17 |
| 2011 | 29 |
| 2012 | 20 |
| 2015 | 15 |
| 2016 | 16 |
| 2021 | 6 |
| 2022 | 20 |
| 2023 | 11 |